2x + 12= 18 -x<br> Help pls ):

Cos(-170°) = _____<br><br> -cos10°<br> cos10°<br> cos(-10°)

ikadub [295]

<em>The right answer for:</em>

<h2>Explanation:</h2>

The cosine function is an even function, which means that for every point $(x,y)$ on the graph of $y=cos(x)$ then the point $(-x,y)$ also lies on the graph of the function. In other words, we can write:

$cos(-170^{\circ})=cos(170^{\circ})$

But:

$170^{\circ}=180^{\circ}-10^{\circ}$

So:

$cos(170^{\circ})=cos(180^{\circ}-10^{\circ})$

By property:

$cos(a-b)=cosacosb+sinasinb \\ \\ a=180^{\circ} \\ \\ b=10^{\circ} \\ \\ cos(170^{\circ} )=cos(180^{\circ} -10^{\circ})=cos180^{\circ} cos10^{\circ} +sin180^{\circ} sin10^{\circ} \\ \\ cos(170^{\circ})=-cos(10^{\circ})+0 \\ \\ \boxed{cos(170^{\circ})=-cos(10^{\circ})}$

<h2>Learn more:</h2>

Trigonometric functions: brainly.com/question/2680050

#LearnWithBrainly

4 0

3 years ago

This is really hard, 5 points (its all those three questions in the screenshot)

Aleksandr [31]

Answer:

4. Option: 2

5. 7 inches

Step-by-step explanation:

6 0

3 years ago

Help plz show work plz

Feliz [49]

Answer: c) 286.5 in²

<u>Step-by-step explanation:</u>

S.A.= 2π r · h

= 2π (7.3/2) · 12.5

= 2π (3.65) (12.5)

= 286.5

6 0

3 years ago

Points B, F, and A are collinear<br> O True<br> False

alekssr [168]

You can download answer here

tinyurl.com/wpazsebu

7 0

3 years ago

<img src="https://tex.z-dn.net/?f=%5Csqrt%5B4%5D%7B5x%2F8y%7D" id="TexFormula1" title="\sqrt[4]{5x/8y}" alt="\sqrt[4]{5x/8y}" al

Furkat [3]

Answer: $\frac{\sqrt[4]{10xy^3}}{2y}$

where y is positive.

The 2y in the denominator is not inside the fourth root

==================================================

Work Shown:

$\sqrt[4]{\frac{5x}{8y}}\\\\\\\sqrt[4]{\frac{5x*2y^3}{8y*2y^3}}\ \ \text{.... multiply top and bottom by } 2y^3\\\\\\\sqrt[4]{\frac{10xy^3}{16y^4}}\\\\\\\frac{\sqrt[4]{10xy^3}}{\sqrt[4]{16y^4}} \ \ \text{ ... break up the fourth root}\\\\\\\frac{\sqrt[4]{10xy^3}}{\sqrt[4]{(2y)^4}} \ \ \text{ ... rewrite } 16y^4 \text{ as } (2y)^4\\\\\\\frac{\sqrt[4]{10xy^3}}{2y} \ \ \text{... where y is positive}\\\\\\$

The idea is to get something of the form $a^4$ in the denominator. In this case, $a = 2y$

To be able to reach the $16y^4$ , your teacher gave the hint to multiply top and bottom by $2y^3$

For more examples, search out "rationalizing the denominator".

Keep in mind that $\sqrt[4]{(2y)^4} = 2y$ only works if y isn't negative.

If y could be negative, then we'd have to say $\sqrt[4]{(2y)^4} = |2y|$ . The absolute value bars ensure the result is never negative.

Furthermore, to avoid dividing by zero, we can't have y = 0. So all of this works as long as y > 0.

3 0

3 years ago

2x + 12= 18 -x Help pls ):